Numeric not handling trailing zeros

.chronus/changes/fix-numeric-not-handling-trailing-zeros-2024-4-16-2-43-25.md

@@ -0,0 +1,8 @@
+---
+# Change versionKind to one of: internal, fix, dependencies, feature, deprecation, breaking
+changeKind: fix
+packages:
+  - "@typespec/compiler"
+---
+
+Numeric not handling trailing zeros and causing freeze(e.g. `const a = 100.0`)

packages/compiler/src/core/numeric.ts

@@ -118,14 +118,17 @@ function parse(original: string): InternalData {
     }
 
     let end = stringValue.length;
-    while (stringValue[end - 1] === "0") {
-      if (end < adjustedPointIndex) {
+    let index = end;
+    while (stringValue[index - 1] === "0") {
+      if (index < adjustedPointIndex - 1) {
         // if we are looking at a zero before the decimal point, we need to decrease the exponent
         exp++;
       } else {
         end--;
       }
+      index--;
     }
+
     try {
       stringValue = stringValue.slice(0, end);
       stringValue = stringValue + "0".repeat(Math.max(exp - stringValue.length, 0)); // add remaining zeros for cases like 3e30

packages/compiler/test/core/numeric.test.ts

@@ -39,6 +39,11 @@ describe("parsing", () => {
     it("simple decimal", () => {
       expectNumericData("123.456", 123456n, 3);
     });
+
+    it("decimal with trailing zeros", () => {
+      expectNumericData("100.0", 100n, 3);
+    });
+
     it("negative decimal", () => {
       expectNumericData("-123.456", 123456n, 3, -1);
     });